1. Field of Invention
The present invention relates generally to mobile communications and, more particularly, to a system and method for monitoring paging signals transmitted from a mobile switch to a cell site for occurrences of congestion.
2. Description of the Background
As mobile telephones have grown from mere voice communications devices to sophisticated appliances for paging, text functions and Internet access, bandwidth management has become a critical function for providing Quality of Service (QoS). A wireless communications network typically includes a mobile switch, a paging area, and a cellular device such as a cellular telephone. The mobile switch manages traffic between cellular users. The paging area includes a plurality of cellular telephone transmitters, or cell sites, that cover a certain geographical area. In operation, the mobile switch directs a page, addressed to a certain cellular device, to the appropriate paging area. A cell site, within the paging area, then broadcasts the page, causing, for example, a cellular phone to ring. In practice, network congestion occurs between the mobile switch and a cell site, due in part to limited bandwidth between the switch and the cell site. Such congestion may cause pages sent from the switch to a targeted cellular device, via the cell site, to be lost. Lost pages cause users of cellular devices, such as cellular phones, to miss calls because the phone fails to ring. Paging congestion, therefore, significantly affects QoS. Additionally, paging congestion can lead to substantial revenue losses for telecommunications service providers that fail to collect for unconnected calls.
A mobile switch may communicate with a cell site over a T-1 line. A T-1 line is a commonly used digital line that bundles 24 channels called DS0s, where each DS0 is capable of transmitting 64 kbps, for an overall transmission rate of 1.5 Mbps. Some wireless communication networks, however, may limit paging communications to just one of the 24 channels in a T-1 line, reserving the other 23 channels for transmitting voice data. The growing popularity of cellular phones has caused the DS0 channel dedicated to paging to operate at or beyond its 64 kbps capacity. New services, such as short messaging service and message waiting indicators on cellular phones, also share the same DS0.
A network diagnostic tool is needed that enables service providers to identify, and even quantify, instances of paging congestion. Such a system needs to provide sufficient flexibility to identify paging congestion problems that exceed certain quantitative thresholds. Such a system also needs to provide a notification system in which certain network operators receive timely alerts when a paging congestion problem occurs. The present invention satisfies this need.